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Motorcycle Painting 101

Painting a motorcycle may at first seem like an intimidating DIY project, but with a little time and effort, anyone can learn to do a decent spray-can paintjob. This gives you the pride of having done it yourself, and the savings of not having paid someone else to do it. Granted, there are some limitations to doing the spray-can job (color options, finish options, etc), but you don’t have to have a big air-spray setup and also don’t have to worry about the overspray, re-coat, and cleanup issues associated with a HVLP (high volume low pressure) air setup.

A little background info on my painting experience: my motorcycle painting is limited to my wife’s GN400, my Yamaha Seca and my Honda Superhawk (both flat finish). That said, whether you’re shooting flat finish or a multi layer color change-scheme (wife’s bike), there are some basic guidelines you can follow to make your life easier. Plan to spend about 70% of your involved time on prep, and about 30% on actually spraying. The spray period may actually take longer than the prep, but a large portion is waiting on paint to tack/dry/cure, so I don’t count that time.

Prep

This is by far the most important step in getting a paint job to look good. The objective is to remove any surface blemishes, be that a sticker, rash, cracks, etc, and make the surface as smooth as possible for paint. For starters, take everything COMPLETELY apart. This means every little rubber grommet, screw, etc needs to come off. This is so you can spray the entire piece, and so you don’t get paint on the rubber bits (which are not always agreeable with paint. After you’ve got everything in pieces, you want to remove any surface stickers. This can be aided by the use of a hair dryer to heat the sticker and render the adhesive more willing to let go. In this pic, you’ll notice that there was a section of adhesive still on the bike. This was from the original sticker that had been removed before the newer one had been applied. Since it was an original sticker (from the factory) and had been on the bike over 2 years, the adhesive was much less willing to come off.

After removing any stickers, you’ll want to scuff the entire surface to be painted. Fresh paint doesn’t like to stick to shiny finish, and scuffing also helps remove any surface unknowns like leftover wax or cleaner. I’ve found that 400-grit is the magic number, as any lower grit and you run the risk of ‘scratching’ instead of scuffing, and any higher is not going to help in removing anything like stubborn adhesive or the like. If you’ve got larger/deeper nicks and scratches, or rock chips like my VTR did, you’ll need to use Bondo. Contrary to popular belief, Bondo is your friend when it comes to a good paint job. However, if you’re not doing a large job, I’d definitely recommend getting some glazing and spot putty. It’s pre-mixed, which means you don’t put in have to worry about screwing up the hardener ratio, and it comes in a tube, which is generally easier for controlling the amount of Bondo you put on an area. Squeeze a small amount onto a paint chip/crack/etc and then contour it along the surface with a plastic scraper. Also, once the Bondo loses its initial pliability, STOP SCRAPING. You’ll pull little fissure cracks along behind the scraper and these are a major pain to sand out. Finally, apply in thin layers (The dent on top of the wife’s tank has 5 layers on it), because it dries much faster this way, and it’s easier to sand down a little than wait for a thick layer to dry and possibly pull the upcoming move: //BONEHEAD ALERT: Let the Bondo dry completely before sanding it. The first time you begin sanding and fold the semi-dry Bondo and/or gouge a valley, you will want to kick yourself. Hard. If you pull this move, you have to let that Bondo dry, then sand, then re-apply, which you may not have had to earlier.// Save yourself some time in the long run and wait a couple more minutes when you think it’s “dry enough”. If you’ve not been too smooth with your plastic scraper, you can start with 200-grit (or 150 even) for rough edge removal, but once you get closer to the finished surface you want, get back up toward the 400-grit stuff. Smooth the Bondo, the transition to the regular surface, and then make sure the rest of the surface is “400-grit smooth”. Once you do any bit of sanding, you’ll get a feel for what’s right. If it feels funny, sand it smoother. You’ll definitely notice in the next step.

Spray

This is the “fun” part of painting, because you can see the fruits of your hard prep work come to life. Spraying the paint is the most fun, but is also the most hazardous. Seriously. Want to kill some brain cells? Ignore the directions on the paint can that say to spray in a well ventilated area. This is of course sarcasm, paint fumes are bad news. Here’s a pic of my spray area, and another of the vent setup I’ve got for when I’m spraying. As you can see, I’ve got a window with a fan blowing out, high up, and fairly near my spray table. This takes the fumes OUT. It also helps some with overspray, since lots of the little particulates that don’t immediately hit the parts get wafted away instead of drifting down and making the surface rougher. This helps later in the finishing stage.

A quick note about paints: Most of the stuff you’re going to find at the local auto hobby or Meijer/Walmart/Kmart are enamels of one sort or another. There are issues if you spray enamels and lacquer based paints on top of each other. I can’t remember which one can go over the other and not vice versa, but a general guide is just to not mix them. Once you’ve got the color picked out, spraying is divided into Primer, Color, and Clear. Sometimes color and clear are the same step (depending on the paint), but you definitely need to primer before the other steps, ESPECIALLY if you have any Bondo involved. //BONEHEAD ALERT: Spraying only a color coat over Bondo is a really, really bad idea. Bondo is very porous, and without sealing it with a primer coat, it will soak the color out of the paint.// I used some OD green I had as a basecoat for my Superhawk, thinking I could get away with that as my ‘primer’. This is what the front fender looked like after 2 coats of green and 3 of black. Notice the light spot? It took a total of 6 coats of black to get the color uniform. On the fairings and tank I wised up and shot some primer over the Bondo and Voila! No soakage! You can get deep fill primer for deeper scratches, or filler primer for light scratches, or regular primer, but I’d recommend spending the time sanding the surface and Bondo very well before you primer, and save yourself the hassle.

Once you’ve got the primer shot, let it dry. If it’s the same type as your color coat, you can start shooting color after its kinda dry, within the recoat window. This means you either have to let it mostly dry and shoot it (usually in under an hour) or let it cure and then start the color (1-2 days, depending). Primer doesn’t always have this long restriction on re-coat, which is a good thing, but make sure you read all the labels. Once you start shooting color however, you’re locked into the recoat windows laid out on your paint label, so make sure you’ve either got the time to finish, or the time to let it sit to finish later. And since we’ve had one in each section so far, //BONEHEAD ALERT: Spray multiple thin layers.// I can’t stress this point enough. Smoothing out 4 thin layers where each one almost completely covered the last is 1000 times easier than fixing the run you put in the paint because you just wanted to “color that whole area on this pass”. Runs suck. Period. If they’re bad enough, you may have to let everything cure, sand that area down to the primer and re-spray. Save yourself this headache and just spray light layers. A good guide is that the surface looks like it’s about to be completely wet. Once it gets ‘completely wet’ any extra paint threatens to be too much for an area, and then the run happens. Believe me, that little speck you missed on the first coat after primer WILL get filled in a subsequent coat. Let it go. Better yet, find some scrap metal/plastic to practice spraying. If it’s your first attempt at paint, this will help immensely.

After the color coat is dry, it’s time to shoot clear/topcoat. One way to make this look especially good is to let the color dry sufficiently to allow wet sanding, then hitting it with at least 1000-grit or higher wet sandpaper. Make sure you rinse the sandpaper often, as any particulates at this level can scratch, which is bad. If you sand, make sure you wipe the surface down really well before you start spraying again. I’ve found the blue shop-towels that come on a roll are great for this. They tend to be softer than regular paper towels, and won’t leave fuzzies behind. Apply the clear in the same manner as the color, within the prescribed recoat windows. For the wife’s bike I used purple Duplicolor Metalcast ‘anodized’ topcoat over Harvard-Blue Pearl Honda Accord paint, and it turned out good. Whatever finish paint you use, let it cure completely before you go any further (usually 1-2 days, depending). For that final shine, wet-sand with at least 1500-grit, or use polishing compound (similar to, but finer than rubbing compound) usually found with the cleaners at the auto parts store. Next hit it with a buffer, then some wax. From what I understand, it’s advisable to wait another day or so between the polishing/buffing and wax, just to make completely sure the paint has cured.

So, to review:
1. Prep is 70% of the involved time, and is by far the most important component to a good looking finish.
2. Pay attention to drying times for Bondo and primers in order to save time due to gouges/screwups.
3. Sand everything until “400-grit smooth”
4. Make sure you spray primer over Bondo
5. Spray thin coats of color to avoid runs.
6. Wet-sand before clear for smoother finish
7. Let it cure, then polish/buff/wait/wax/smile.
8. Smirk when someone asks who did your cool new paint job!